This invention relates to computer memory, and more particularly to a method for fabricating phase change memory cells.
Phase change memory cells are known to have failure modes. One example is an endurance failure that occurs after cycling a phase change memory cell many times between the crystalline (SET) and amorphous (RESET) states. Phase change memory cycling results in the phase change material becoming disconnected from an electrode and causing the cell to be electrically open with no current passing through. A root cause of this failure is a separation of the phase change material from a bottom electrode material.
Another example is a process induced failure leading to delamination of a phase change material. In this failure mode, high temperature processes throughout the processing of an integrated structure cause the phase change material shrink and form voids at corners. This causes the phase change material in the phase change memory cell to delaminate at its interfaces leaving the cell electrically open with no current passing through.